Sorcery, as it's presented in the core rulebook of Basic RolePlaying, is actually a small subset of a much larger set of options broadly outlined in the Stormbringer and Elric! roleplaying games. For those familiar with Call of Cthulhu, which also uses sorcery, the biggest difference is the variety of offensive, defensive and utility spells available. CoC tends to view sorcery as something performed under special conditions, requiring detailed rituals and much preparation. Except for a handful of offensive and defensive spells such as the Elder Sign, most CoC spells involve contacting various Mythos entities or summoning/binding servitor races. For this reason, sorcery is a pursuit best avoided by most right-thinking characters in Call of Cthulhu, except in cases of extreme duress. And, of course, the very act of performing sorcery in CoC has a corrosive effect on one's sanity.
In BRP and Stormbringer, sorcery is more common and has no sanity implications, although the requisite POW score is prohibitive, ensuring that sorcerers are a rare breed. There are three main types of sorcery and typically, a high-level sorcerer will be adept in all three. These are spells, runes and summonings. Spells represent the default form of sorcery, the type to which most low-level sorcerers will be limited. Spells have the advantages of being quick to prepare and demanding modest power point expenditures, although durations are quite short. This is the type of sorcery used most often in combat.
Runes, as the name implies, require the preparation of an inscribed symbol which will trigger a sorcerous effect when certain conditions are met. Runes can persist for days or even years until triggered, making them useful for setting traps. Some runes duplicate the effects of spells, while others offer unique options such as wards or alarms. Most forms of Lawful sorcery are runic.
In game terms, summonings work just like spells, except they are more detailed and require greater preparation. In that respect, they are similar to Call of Cthulhu sorcery. Sorcerers can summon demons or elementals. There are also some necromantic summonings which allow a sorcerer to summon spirits to inhabit prepared corpses or even living hosts. In the latter case, the spirit of the victim is destroyed and the summoned spirit takes possession of the body. The newly-created undead is then bound to the service of the necromancer. Summoned entities are often bound, either in their living state or as the animating essence of some powerful magic item. The summoner has to spend enough power points to define the summoned creature. A fully-formed demon servant will be more costly because points will have to be spent to define physical characteristics such as STR, SIZ, CON, DEX and Move as well as POW and INT. Such a demon would require far more power points than even the most powerful sorcerer would have available. Therefore, a means of storing power points is needed to cast summonings. This requires significant preparation. Also, binding demons, elementals and undead requires the sacrifice of POW points. This is a particularly demanding requirement and one only considered by truly powerful summoners.
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